pcIRT

The R package pcIRT provides functions that estimate the following IRT models:

  • Multidimensional Polytomous Rasch model (MPRM) (Rasch, 1961)

MPRM is a multidimensional IRT model for multicategorical data. For each response category, a latent dimension is assumed. The item characteristic curves of an example looks like this:

  • Continuous Rating Scale model (CRSM) (Müller, 1987)

CRSM is an extension of the Rating Scale model. It can be used to analyze items with a visual analogue scale for example.

  • Dichotomous Logistic Rasch model (Rasch, 1960)

By defining the design matrix, restricted Rasch models (e.g. the Linear Logistic Rasch model) can be estimated, too.

Download

pcIRT is available on CRAN. The developer version can be downloaded from my Github Site.

Publication

pcIRT (especially the application and usage of the MPRM) is described and illustrated in this paper